The peristaltic pump was developed in the 1930′s by a medical student, who later became a noted heart surgeon. He recognized the need for a positive displacement pump which would negate cross contamination between the pump mechanism and sterile fluids. Progression of the art eventually led to three basic types of peristaltic pumps.
In a rotary peristaltic pump, fluid in a flexible tube is contained within a circular pump housing along in its internal circumferential area. A revolving series of rollers compresses and closes the tube, forcing the fluid ahead of the roller to be moved out of the pump exit and the tubing immediately following the roller to be returned to its normal expanded state (process called peristalsis), thereby drawing fluid into the pump through the pump inlet.
In a circular peristaltic pump, a single roller on an eccentric compresses the tubing through a full 360 degrees of rotation. This is accomplished by a roller with increased width contacting the slightly spiraled tubing within the pump housing.
Linear peristaltic pumps have typically used a series of sequential cam driven fingers to effect the peristaltic pumping action. Some variations to the linear peristaltic pump actions include systems which compress the tube between a flat platen and a series of belt mounted rollers which are successively driven along the platen. Another variation of a linear peristaltic pump attempts to utilize the traditional circular roller motion to achieve a linear pump. In this pump, a pair of shaft mounted rollers interacts with the tubing affixed to a spring loaded pivotal pump arm which moves under the influence of the rollers. As the rollers reach a position in which they are not occluding the tubing a fixed stop device occludes the tube, thereby preventing any back or forward flow until the next cycle of rollers contacts and occludes the tubing. The problem of combining the simplicity of the circular mechanism in a linear peristaltic pump has remained unanswered.
There have been many in the prior art who have attempted to solve these problems with varying degrees of success. None, however completely satisfies the requirements for a complete solution to the aforestated problem. The following U.S. patents are attempts of the prior art to solve this problem.
U.S. Pat. No. 2,446,618 to Stocks discloses pumps which are particularly suitable for use in moving sludges, slimes, and other fluids carrying a large amount of solids. The invention teaches a pump in which the pressure chamber is collapsed progressively, and continuously in the direction of he flow of the material being pumped.
U.S. Pat. No. 3,249,059 to Renn discloses a new and improved peristaltic pump. The invention teaches a new and improved means for supporting and guiding the planetary roller assembly which compresses the length of collapsible tubing.
U.S. Pat. No. 3,366,071 to Dutler discloses a peristaltic or tube squeezing pump of the planetary type, i.e. it has rollers without individual bearings and contacting a central driving member which preferably is circular. The rollers are arranged to roll on the tube and on a rolling face along different portions of their travel. In each roller the portion contacting the tube has a slightly greater diameter than the portion contacting the rolling surface so that a slight recoil movement of the tube contacting portion is produced while the roller is rolling on the rolling face.
U.S. Pat. No. 3,876,340 to Thomas discloses a peristaltic pipe in which there are several side-by-side flexible pumping tubes each having its own set of pumping rollers which are moved sequentially into a tube flattening position, along the tube for a predetermined length and then cut out of contact with the tube to perform the pumping action. Each tube has its own support against which it is pressed by the rollers and the support is resiliently yieldable in order to avoid placing excess flattening pressures on the tube. In a preferred case, each support is a spring loaded block which may be of resilient material, each set of rollers is carried on a rotatable spider, and the spiders are rotatable simultaneously.
U.S. Pat. No. 4,165,954 to Amos discloses a linear peristaltic pump. The pump includes a pivotal pump arm and a flexible tube secured thereto to inhibit longitudinal tube movement. A means for applying a force to such arm, such as a spring, is provided to cause the pump arm to pivot. A stop device is disposed in the path of travel of the pump arm so that the pump arm pivotal travel may be terminated as the pump arm comes to rest against such stop device. The flexible tube is disposed adjacent a surface of the pump arm and is pivotal therewith so that the flexible tube is pinched off between the pump arm surface and the stop device as the pump comes to rest against it. A rotatable roller assembly is provided having at least one roller mounted on a rotatable roller support. The roller intermittently contacts the flexible tube as the roller support is rotated causing a quantity of liquid to be peristaltically moved within the tube. The pump arm may have a concave surface to accommodate the flexible tube and the convex surface of the roller, if desired. The stop device may be adjustable so as to permit adjustment and change of the pivotal travel of the pump arm. The rotatable roller assembly may be caused to intermittently contact the flexible tube through the use of an electric clutch to which the roller assembly is rotatably responsive. The rotatable roller assembly causes the pump arm and flexible tube to pivot in a direction away from the stop device while the means for applying a force causes the pump arm and flexible tube to pivot in a direction towards the stop device.
U.S. Pat. No. 4,493,706 to Borsanyi et al. discloses a linear peristaltic pump, and a disposable cassette therefore, particularly suitable for the infusion of parenteral fluids. The pump includes a housing having a power-driven shaft and a series of small bearing assemblies having their inner members eccentrically mounted upon that shaft. A thin elastomeric membrane extends along the series of bearing assemblies for engagement with the outer members thereof along a first band or linear zone of contact lying in the same plane as the axis of the shaft. The disposable cassette is removably supported by the housing and takes the form of a rigid, planar, parametric frame having an opening across which is stretched a section of elastomeric tubing. Locators provided by the housing and frame orient the cassette with the axis of the tubing in the same plane as the first band of contact and the axis of the shaft, and a platen provided by the housing engages the section of elastomeric tubing that bridges the opening of the frame to urge that section into engagement with the opposite side of the membrane along a second band or linear zone of contact parallel with the first band of contact. The cassette may include tubular extensions and connectors for connecting opposite ends of the section of elastomeric tubing to a source of fluid and to a patient.
U.S. Pat. No. 4,715,435 to Foret discloses a method and apparatus for pumping and exchanging heat at an accelerated rate between two fluid streams. The apparatus comprises opposite peristaltic pumps moving a separate fluid on their respective side of a linear heat-conductive platen. Each pump consists of a flat elastomeric diaphragm clamped by its edges on the platen; the clamping squeeze displaces the elastomer and makes the diaphragm bulge. Closely spaced pins in combination with fixed cams, flatten and contract the bulge across to form a variable cross-section working chamber. Inlet and outlet are formed by the elastomer bulging into end block cavities leading to ports. In a typical operation, conveyed rollers depress the pins which in turn completely contract the bulge to sealing contact with the platen and forms shrinking volumetric chambers, wherein a gas or mixed-phase fluid is compressed progressively on one side of the platen; on the other side similar operation occurs but volumetric chambers circulate a non-compressible liquid. During operation, heat of compression is simultaneously rejected to the cooling liquid through the platen to achieve a near-isothermal process.
U.S. Pat. No. 4,921,477 to Davis discloses a surgical irrigation and aspiration system for aspirating fluid from a surgical site, such as the eye, including a surgical tool having irrigation and aspiration functions, and an irrigation fluid supply for providing irrigation fluid to the surgical tool. A peristaltic pump pumps aspiration fluid from the surgical site generally through and away from the surgical tool and through an aspiration flow line to a collection container. A dampening mechanism in the aspiration flow line before the pump dampens the oscillations of the aspiration fluid flow, caused by the inherent operation of the peristaltic pump, in the aspiration flow line, and thereby at the surgical site.
U.S. Pat. No. 5,044,902 to Malbec discloses a cartridge comprised of a housing which comprises, in the vicinity of each of its ends, a cylindrical raceway against which are capable of applying and rolling bevel gears which crush the flexible tube located between both raceways. The bevel gears are tubular and freely mounted inside the housing, within the concavity of the flexible tube, this housing comprising, at least on one side, a central opening with a diameter large enough to enable the driving of the bevel gears either directly from a rotary disc provided with planet gears capable of engaging into the tubular bevel gears or from a shaft internally engaged between the tubular bevel gears.
U.S. Pat. No. 5,054,947 to Frank, et al. discloses a self-contained power painting system in which a battery operated motor and pump are contained in a lid for a paint reservoir, and that entire unit is adapted to be carried on a user by a strap or belt. A paint applicator, such as a brush or roller, is connected to the pump by a flexible conduit and includes a switch activator at the applicator to permit the user to selectively control operation of the pump and to move about freely while painting without being encumbered by a relatively immobile paint reservoir or power source connection through extension cords.
U.S. Pat. No. 5,096,393 to Van Steendren, et al. discloses a peristaltic metering pump for dosing metered quantities of fluids along a plurality of flow lines. The pump comprises a set of rollers and a plurality of flexible liquid transfer tubes, the tubes being mounted on a tube mounting against which they are simultaneously compressed by the rollers. The rollers are drivingly connected to a motor, the rollers being mounted on a roller support. The motor is operable to drive the rollers so that they roll successively along the tubes and compress the tubes simultaneously against the tube mounting as they roll along the tubes. The roller support is biassed against a stop with the roller support being movable away from the stop against the bias by force exerted on at least one roller by the tubes.
U.S. Pat. No. 5,924,852 to Moubayed et al. discloses a peristaltic pump for pumping liquids through a resilient tube. In one embodiment, the pump includes a curved concave platen against which a resilient tube is placed. A multi lobed cam is positioned adjacent to the platen and tube. A plurality of pump fingers are mounted between tube and cam in a manner permitting radial movement of the pump fingers. As the cam rotates, the fingers are pressed toward the tube sequentially so as to pump liquid through the tube. The lobe end should press the tube sufficiently to occlude the tube and prevent back flow without over pressing and damaging the tube. A transverse pinch finger is provided on each pump finger, extending from the tube pressing face of each pump finger. At the tube occluding position, the pump finger nearly occludes the tube and the pinch finger completes occlusion without pressing the tube beyond the fully occluded position. A fixed or slidable spring pressed pinch finger may be used. In a second embodiment, the pump fingers also include pinch fingers and are moved toward and away from a planar platen by a plurality of cams mounted transversely on a rotatable shaft. The pinch fingers operate in the same manner as in the first embodiment.
U.S. Patent Application 2006/0228240 to Schroeder, et al. discloses a method and accompanying apparatus for dispensing product with a non-invasive linear peristaltic pump. The linear peristaltic pump includes a traction plate having a linear portion, a depressor and a driver. The depressor compresses the product tube between the linear portion and the depressor, such that an inner passage of the product tube is substantially sealed. The driver moves the depressor along the linear portion of the traction plate, such that the product tube located between the depressor and the linear portion is compressed along the linear portion. Product in an inner passage of the product tube is thereby moved or dispensed. Another embodiment may include depressors attached to belts, wherein successive depressors may be driven along the linear portion to dispense or move the product. A method for using a linear peristaltic pump and the use of a controller to dispense product is also provided.
U.S. Patent Application 2008/0319394 to Yodfat et al. discloses an infusion system, method and device for infusing therapeutic fluid into the body of a patient. The device includes a driving mechanism including a plurality of gears, wherein at least one gear is adjacent to another gear. The device includes a gear in the plurality of gears having plurality of teeth and at least another gear in the plurality of gears having a plurality of teeth. The plurality of teeth of another gear interact with the plurality of teeth of the gear. At least one tooth in the plurality of teeth of the gear is elastically deformable for causing at least one tooth to elastically deform upon meshing with a tooth in the plurality of teeth of another gear and further for causing reduction of noise associated with operation of the driving mechanism.
U.S. Patent Application 2009/0074597 to Baecke discloses a roller pump which comprises an abutment, at least one roller and a casing. A pump hose is squeezed between the roller and the abutment. A hinge connects the abutment and the casing pivotably, the axis of the hinge being parallel to the plane of the pump hose. The invention further relates to a roller pump which comprises a resilient roll member which is fixed to the abutment. The pump hose is pressed against the resilient roll member. The invention additionally relates to a roller pump which comprises two roller gears. Each roller gear being torque-proof connected to one of the two rollers. The two roller gears engage with another gear for ensuring zero relative velocity of the portion of the rollers squeezing the pump hose with respect to the squeezed portions of the pump hose. The invention finally relates to a roller pump which comprises a drive train for mechanically connecting a motor and the rollers. The drive train comprises a sliding hub for limiting the transmitted torque.
Although the aforementioned prior art have contributed to the development of the art of peristaltic pump, none of these prior art patents have solved the needs of this art.
Therefore, it is an object of the present invention to provide an improved linear peristaltic pump.
Another object of this invention is to provide an improved linear peristaltic pump utilizing a rotary driving mechanism.
Another object of this invention is to provide an improved apparatus that is simple for the operator to use.
Another object of this invention is to provide an improved apparatus that is easy to cost effectively produce.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention with in the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment of the invention.